Formation testing tool for oil wells and the like



H. E. PHILP 2,034,957

FORMATION TESTING TOOL FOR OIL WELLS AND THE LIKE March 24, 1936.

2 Sheets-Sheet 1 Filed July 14, 1934 I III,

INENIOR:

H. E. PHILP March 24, 1936.

FORMATION TESTING TOOL FOR OIL WELLS AND THE LIKE Filed July 14, 1954 2 Sheets-Sheet 2 A I J I 4 7 ,/0// A/ Patented Mar. 24, 1936 PATENT OFFICE FORMATION TESTING TOOL FOR OIL WELLS AND THE LIKE Hubert E. Philp, Shreveport, La., assignor of one-half to Mabel R. Spellman, Dallas, Tex.

Application-July 14, 1934, Serial No. 735,117

12 Claims.

This invention relates to formation testing tools for oil wells and the like and has for its object to improve generally upon tools of this character and to attain certain advantages as will hereinafter more fully appear.

The general object of this invention is to produce a tool of simple and inexpensive construction, which is easily manipulated and highly eflicient for the purposes intended and greatly minimizes the liability of losing the well through a mishap in using the tool.

A specific object of the invention is to produce a tool operating on a principle which permits its adaptation for the taking of a sample from the normal bore of a well hole proper or from a smaller bore in the formation commonly termed a rat-hole, and, to this end, adaptations of the invention to both types of tools are illustrated in the accompanying drawings.

Another particular object of the invention is to provide for the ready removal of the stem tubing or manipulating column which extends up above the top of the well, in an emergency or when it is particularly desired to leave the outer part of the tool seated in the well hole proper or the rat-hole, as the case may be, as will be later herein more fully described.

A further object of the invention is to provide a tool of the character described of a construction whereby the outer tubular portion thereof may be left in place at the bottom of the hole, and there cemented or otherwise secured and sealed according to any approved practice, and upon which the usual well lining tubing is seated at its lower end after the drilling operations are completed and the well is brought in, as it is termed, if the prospect materializes.

Other particular objects and material advantages in the present invention will hereinafter more fully appear.

The invention consists in the application of the principles and in the broad construction em-- bodying the same as well as in the special parts and combinations and arrangements of parts as hereinafter described and pointed out with particularity in the appended claims.

In the accompanying drawings, illustrating practical adaptations of the invention,-

Figure 1 is a side elevation of thetool as adapted for taking a sample of the cognate fluid from the formation in the main bore of the well;

Figure 2 is a vertical section of the tool illustrated in Figure 1;

Figure 3 is a transverse section taken on the line 3-3 of Figures 1 and 2;

Figures 4 and 5 are transverse sections taken respectively on the lines 4-4 and 5-5 of Figures l and 2, to show the normally closed correlation of the cooperative inlet openings of the irmer and outer tubular elements of the tool; 5

Figure 6 is a top plan view of the bottom end closure element detached from the tool;

Figure 7 is a view similar to Figure 3 but showing the inner tubular element of the tool rotated to bring the key-studs thereof into line with the vertically elongated guide-slots of the outer tubular element of the tool;

Figure 8 is a section taken on or about the line 5-5 of Figures 1 and 2, after the inner tubular member has been moved downwardly in the outer tubular member to bring the inlet openings of said tubular members into communicable registration;

Figure 9 is a side elevation, with parts in vertical section and with portions broken away, illustrating an adaptation of the invention 'to a rat-hole type of testing tool;

Figure 10 is a vertical longitudinal section of the tool illustrated in Figure 9;

Figure 11 is a transverse section on the line H-ll of Figures 9 and 10; and

Figure 12 is a transverse section on the line l2--l2 of Figures 9 and 10.

Referring now more particularly to Figures 1 to 8, inclusive, of the drawings, the numeral I designates the outer tubular element or liner of the testing tool, at the lower end of which is provided a closure element 2. Preferably, as shown, this closure element 2 comprises an internally screw-threaded collar which is fitted onto the externally screw-threaded end portion of said tubular element l. The collar element 2 is provided with a transverse partition 3 having a, series of apertures 4 therein, said apertures being normally closed by a downwardly opening 0 valve member 5. This valve member 5, the function of which will be later more fully described, is normally held yieldably in closed position by having a central stem portion 6 slidably fitted in a central opening in the partition 3 of the collar 5 element 2, said stem portion 6 having a, spring I coiled thereabout and interposed, under compression, between the upper face of the partition 3 and a thrust collar 8 which is secured on the upper end portion of said stem 6 by a nut 9.

Fitted to rotate and slide longitudinally within the outer tubular element l is an inner tubular element or liner l0, said elements being provided with inlet openings normally out of communicable registration with each other and the open- 65 ings in the one element being normally closed by the wall of the other element. As shown, the openings in the outer element I are relatively small, circular apertures arranged in parallel vertical series, as at II, in Figure 1, and the openings in the inner tubular element ID are in the form of vertically elongated slots I2, as shown more clearly in Figure 2. In the normally closed relation of said openings II and I2, the inner tubular member I0 is supported with its lower end I3 raised from the partition 3 of the collar member 2, in which position the inlet slots I2 are at an elevation with their lower ends slightly above the uppermost apertures II in the outer tubular element" I, and are out of vertical alignment with the respective series of said openings I I, by which arrangement the inner tubular element I 0 must be given a partial rotation within the outer tubular element I to bring said slots I2 into vertical alignment with said vertical series of apertures II.

In the outer tubular element I two diametrically opposite, vertically elongated slots I4 are provided, said slots being so located that, when stud members or lugs I5, extending outwardly from the peripheral face of said inner tubular member ID, are in working alignment in said slots I4, and into which relation with respect to the slots said studs are brought by the aforesaid partial rotation of said inner tubular member III, the inner tubular member is then movable longitudinally within the outer tubular member -I to cause registration and communication between the slots I2 and said apertures II. Ofiset laterally from said vertically elongated slots I4 are relatively short communicating slots I6 in which said stud members or lugs I5 are normally seated, thereby preventing relative end-wise movement between said inner and outer tubular elements I and I 0, respectively.

At the upper end portion of the outer tubular member I a collar I1 is provided to afford a seat for a packer element I8, said collar being preferably hollowed for the reception of the lower end portion of said packer clement I8 and it is provided with an annular retaining flange I9. The packer element I8, may be of any suitable or approved formation but, obviously, of a resilient character whereby to be compressed under endwise pressure and thereby expanded transversely at the middle thereof or between said collar I1 and a similar collar 20 which is secured on the upper end portion of said inner tubular member ID. Obviously, the packer element I8 is fitted loosely about said inner tubular element I0, between said collars I1 and 20, so as to permit the longitudinal sliding movement as well as rotative movement of said inner tubular element with respect to said outer tubular element I as hereinbefore described with reference to the inlet openings II and I2 and slots I4 and studs or lugs I5. The collar 20 is relatively elongated longltudinally as compared to said collar I1, and it is so made in order to perform the dual function of a thrust collar for said packer element I8 and a coupling by which the lowermost section 2I of the tubular stem, which extends upwardly through the well bore, is secured to the upper end of said inner tubular element I0. Obviously, all the pipe connections are secured in the couplings by right hand threads and the turning of the tool and several connected pipe sections is always to the right in the placing of the tool, whereby to practically prevent or at least greatly minimize the liability of accidentally disconnecting the joined elements.

While the tubular elements I and III of the tool are fitted to rotate and slide longitudinally with respect to each other, the fitting is leaktight and offers suificient frictional resistance to prevent or greatly minimize. the liability of accidental rotative or end-wise movement of said elements I and I 0 relative to each other, and the end-wise movement being positively prevented when thestud members or lugs I5 are in the laterally offset slots I6 of said longitudinal slots I4 in the outer tubular element I, as best shown in Figure 1.

In applying the tool to make the test, it is attached to the lower end portion of the lowermost stem pipe 2| and] inserted in the bore of the well through the column of mud-laden liquid, the parts of the tool being in their normal relation as shown in Figures 1 and 2 of the drawings, and said inlet openings II and I2, of course, being closed or out of communicable registration. When the collar member 2 at the lower end of the outer tubular element I of the tool comes in contact with the bottom of the bore of the well, the weight of the string of stem pipes above the inner tubular element II) of the tool, and the interlocking engagement between the inner and outer tubular elements I and Ill afiorded by the stud members or lugs I5 when located in the lateral slots I6 of the outer tubular member, is

such that said outer tubular member is held from rotation by the engagement of said collar member 2 with the bottom of the well bore. In this connection, it is preferable to serrate the lower operator, thereby efiecting corresponding rota- I tion of said inner tubular element III, the stud members or lugs I5 riding out of said lateral slots I6 and into the vertically elongated slots .I4 of said outer tubular element I, whereupon the tubular inner element Ill is free to be moved forcibly by the weight of the string of stem piping or by manipulation of the stem piping through instrumentalities under the control of the operator. As soon as the inner tubular element III has moved a slight distance downwardly in the outer tubular element I, the lower end portions of the slots I2 in said inner tubular element I0 start to register with the uppermost apertures of the respective aligned vertical series of apertures II in said outer tubular element I, and, throughout the continued downward movement of said inner tubular element II], the slots I2 register with the other apertures of the respective series II, thereby progressively increasing the area of inlet.

While the longitudinal movement of the inner tubular member I0 is occurring as just above described, the packer element I8 is being compressed between the collars and 20 and at the same time said packer element is being expanded transversely and brought into sealing engagement with the wall of the well bore as shown by broken lines in Figure 1 of the drawings. The packer as thus engaged with the wall of the well bore effectively prevents the entrance of the mud-laden liquid from above the packer into the lower portion of the well hole. Obviously, therefore, only the cognate fluid from the formation below the packer will enter through the inlet openings H and I2, which are in communicable registration at this time as just above described, and flow upwardly through the inner tubular element I0 and the communicating stem piping thereabove and with no contamination other than the comparatively small amount of mud-laden liquid below the packer element l8 which may enter through the inlet openings H and 2 with the cognate fluid from the formation, said quantity of mud-laden liquid entering the tool being so slight as compared to the volume of the cognate fluid of the formation taken as a sample as to not appreciably hinder the analyzing and determination of the value of the sample.

In Figure 3 of the drawings the stud members or lugs l5 are shown in their interlocking engagement in the lateral slot l6 of the outer tubular member while in Figure 7 the inner tubular member l0 has been turned to bring said stud members or lugs l5 into working relation in the vertically elongated slots l4. When the inner tubular element i0 is thus positioned rotatably and moved endwise downwardly in the outer tubular member the slots l2 of said inner tubular member ID are in communicable registration as shown in Figure 8 and read in correlation with Figure 7.

The cognate fluid taken into the testing tool and headed up in the stem piping 2| is entrapped by moving said stem piping and the attached inner tubular element In upwardly and during which upward movement the stud members or lugs l 5 ride upwardly in said vertically elongated slots l4 and the inlet slots l2 of said inner tubular member ID move out of communicable registration with the respective series of inlet apertures ll of the outer tubular member of the tool. The relative upward movement of the inner tubular member l0 independently of said outer tubular member is arrested when said stud members or lugs |5 come in engagement with the upper ends of said slots l4, said slots |4 being extended slightly above the laterally ofiset slots l6, producing, in effect, laterally shouldered recesses 22 in which the stud members or lugs |5 are seated with interlocking effect to prevent relative rotation between the inner and outer tubular elements I and I0 during the withdrawal of the tool with the entrapped sample from the well.

In practice, the stud elements or lugs l5 are made strong enough to function as guides for the relative rotative and endwise movements between the innerand outer tubular elements and I0 and for limiting such movements, but they are also made relatively soft or frangible so as to be sheared ofi should the tool stick or freeze in the well hole, by exerting sufficient force in rotating or longitudinally moving the stem piping. In this connection, the elongated longitudinal slots I4 in the outer tubular element of the tool are of material advantage in that considerable reciprocatory motion is permitted the inner tubular member It) so that the stud members or lugs l5 may be struck forcibly against the upper and lower ends of the slots l4, alternately, to eifect the breaking off or shearing of said stud members or lugs |5. After the stud members or lugs |5 are thus broken off or sheared the inner tubular member I0 is readily withdrawable from said outer tubular member In Figures 9 to 11 inclusive, of the drawings, the

invention is illustrated as applied in a rat-hole type of testing tool. As shown the tool comprises an outer tubular element 23 having at its lower end a collar 24 which is identical with said collar 2 01 the first herein described tool except that the lower end of said collar 24 is not provided with the serrations or biting portions as shown and described in connection with Figufes 1 and 2 of the drawings. In this modification the outer tubular member 23 is relatively shorter than the outer tubular member of the first herein described tool, and said member 23- is attached to an intermediate tubular member 25 by a collar 26 which is screw threaded internally to receive the correspondingly external screw threaded, meeting end portions of said members 23 and 25, as best shown in Figure 10.

Sleeved loosely on said tubular member 25 is a collar 21 which abuts said collar 26. Also sleeved on said tubular member 25 is a conical packer element 28 whose lower end portion is bevelled to fit in a correspondingly bevelled seat in said loose ring member or'collar 21, the upper end portion of said packer element 28 being also bevelled and seated in a counterpart seat in a loose ring member or collar 29, sleeved on said tubular member 25 and clamped by the lower end portion of a longitudinally elongated collar member 30 which is opposed to said collar member 26.

The lower portion of the bore of said collar member 3| is provided with diametrically disposed,

vertically elongated slots 32, similar in arrangement and general effect to the hereinbefore described slots M of said tubular member and the inner tubular member 33 of this rat-hole type of tool is provided with stud members or lugs 34 similar to the hereinbefore described stud members or lugs IS. The laterally offset slots 35 of this modification are somewhat different in form from the hereinbefore described slots IS in that said slots 35 have their closed in portions turned downwardly to produce an inclined shoulder 36 of sufiicient angularity to resist and prevent accidental rotation of the inner tool 33 within the aligned outer tube members 23, 25'and 3|, yet permitting the stud members or lugs 34 to ride out of said laterally offset slots 35 when due force is applied to the member 33 to effect its rotation.

The slots 32 have their upper end portions extended as at 31, in a manner identical with the end portions 22 of said slots M of the tool first herein described, said slots 32 and 35 functioning in a manner similar to the slots l4 and IS in the operation of the tool. In this modification there is a second laterally offset slot 38 at the side opposite that from which the slot 35 is offset. Preferably, the slot 38 is in a plane a little below that of the slot 35 whereby there is a shoulder 39 opposed to the slot 35 so that, when the inner tubular member 33 is rotated the stud members 34 will engage the shoulder 39 and thereby prevent the entrance of the stud members 34 into the slots 38 while the tool is being operated under normal conditions. Slots 38 have a communication with open-ended longitudinal slots 40 in the upper portion of said tubular member 3|. Y

The collar member not only serves as a ecupling for the tubular members 25 and 3| but it also serves as a reinforcement for the tubular member 3| which is weakened somewhat by the slotting thereof just hereinabove described. By the peculiar formation and correlation of the slots 32, 35, 38 and 40 the same advantages are attained as with the slots I4 and I6 of the first herein described tool structure with the additional advantage of the inclined shoulder 36 to resist accidental rotative movement of the tubular member 33 and the open ended slot 40 permitting the withdrawal of the inner tubular member 33 without first breaking off or shearing stud members 34.

In place of the vertically elongated slots l2, as shown in Figure 2, the inner tubular member 33 shown in Figure 10 is provided with an annular series of inclined or spirally arranged slots 4| which are adapted to register communicably with a similar series of reversely inclined or spirally arranged slots 42 in the outer tubular member 23 as shown in Figure 9. These slots 4| and 42 are normally out of register when the stud members or lugs 34 are in the lateral slots 35 of the tubular member 3|, but, as soon as said stud members or lugs 34 are moved into working alignment in the slots 32, the tubular member 33 is then, of course, movable end-wise downwardly to bring the said slots 4| and 42, which have become longitudinally aligned by the aforesaid rotative adjustment between the tubular members 23 and 33, into communicable registration, the lower end portions of the slots 4| first meeting the upper end portions of said slots 42, after which the said slots 4| and 42 become crossed and continuing to be in communicable registration throughout the downward movement of said tubular member 33 within the tubular member 23.

In this rat-hole type of testing tool the general principle of operation is substantially the same as that of the first herein mentioned type of tool for application in the normal bore of the well, the difierence being that in the tool as illustrated in Figures 1 and 2 of the drawings, the collar member 2 first contacts with the bottom of the well bore, while the packer member 28 of the tool illustrated in Figures 9 and 10 first engages the shoulder at the top of the rat-hole. In either type of tool, should the outer casing member I or 23, as the case may he, become frozen or stuck in the well hole, the inner tubular members I3 and 33 are readily removable by the forcible manipulation thereof to break or shear off the stud members or lugs I5 or by rotating the tubular members to bring the stud members or lugs into the slots so that the tubular members l0 and 33 may be removed from the tool.

Should it be desirable to leave the tubular member I or the corresponding member 23 within the well hole said member is readily cemented or otherwise secured in place by the approved method of fastening a liner or casing member at the bottom of the well hole after the usual drilling operations are finished. However, should the removal of the elements I or 23, as the case may be, be desired or necessary in the continued drilling operations, said. parts may be withdrawn from the well hole by means of the usual tools or appliances employed for such purposes. One parthe well casing or lining ticular advantage of the tool construction in accordance with the present invention is that the outer tubular members I or 23 may be left in the well hole, either because of the accidental sticking thereof or the intentional securing of the same in place, as just herein above described. whereupon further drilling operations may be carried on through the tubular members I or 23, as the case may be, the continuing well bore being, of course, of smaller diameter than the original normal bore of the well hole. So, too, the emplaced tubular members afford practical and satisfactory seats for the lowermost sections of pipes usually placed in the productive well.

In the course of the well drilling operations and particularly while taking the samples of the cognate fluid from the bottom of the well through the instrumentality of the formation testing and sample entrapping tools, as herein generally described, as well as with the highly efficient tool of the present invention, blow-outs often occur due to the flow of the cognate fluid from the formation which is released upon the opening of the inlet apertures of the testing tool, thereby causing caving or pocketing of the adjacent portion of the well bore, and sometimes with serious damaging effect and even resulting in the abandonment of the well. Therefore, provision is made in the tool of the present invention to check such blow-outs and overcome the damaging effect thereof, as will now be described.

As shown more clearly in Figures 2, 6 and 10 of the drawings, the back pressure or check valve 5 normally closes the apertures 4 in the partition 3 of the collar member 2 or 24, as the case may be, said valve being held to its seat by the spring I. Said spring I is obviously of suflicient strength to support the column of the entrapped sample of cognate fluid taken into the tool from the formation as herein described under the normal working conditions. However, should a blow-out occur and evidence thereof be noticed by the operator, as evidence of such a condition usually comes apparent at the top of the well in ample time, he may take steps for the checking thereof, and to this end, the valve 5 is of particular advantage in the tool of the present invention.

In checking the blow-out mud-laden liquid of the same character as that employed in the well bore to prevent caving during the drilling operation is pumped into the stem tubing 2| under sufiicient pressure to displace the cognate fluid which has been taken into the tool and stem piping, at which time, of course, the inlet openings II and I2 or 4| and 42, as the case may be, have been closed by the raising of the tubular members ID or 33. The liquid thus pumped into the tool forces the valve 5 from its seat, against the tension of the spring I, thereby opening the apertures 4, whereupon the mud-laden liquid enters the opening in the formation and holds back the cognate fluid in the formation and effectively checks the blow-out until the liner tube or the outer tubular member of the testing tool can be cemented in place.

It will thus be seen that in the use of the tool of the present invention there is little or no liability of losing the well as sometimes occurs in using tools for testing purposes, because, in most cases, the outer tubular element of the testing tool of the present invention is withdrawable from the well hole, after sticking, by the application of the usual fishing and grappling tools or appliances, or, in case it is not practicable or deconstructions and arrangements herein shown and the oppositely inclined slots 4| and 42, as shown in Figures 9 and 10 of the drawings, the slots may be inclined in the same direction on both the inner and the outer tubular elements, in which cases the longitudinal guide slots M or 32 may be correspondingly inclined to effect the communicable registration of said slotted inlet openings. Furthermore, the tube releasing slotted arrangement 38, 40, of Figures 9 and 10, may be obviously provided below the packer element in the type of tool illustrated in Figures 1 and 2; and, of course, the tool may be modified in other particulars, as just above generally stated, which it is not deemed necessary to here describe in detail.

What is claimed is:

1. A formation testing tool for, oil wells and the like, comprising an inner and an outer tubular member mounted one within the other with relative rotative and endwise movement with respect to each other, said members cooperatively carrying an annular packer element, means for limiting the relative rotatory and endwise movement of said tubular elements, one of said tubular elements having inlet means for the admission of cognate fluid from the formation, and the other tubular element having inlet means for said cognate fluid normally out of communication with the inlet means first mentioned but being brought into communicable registration therewith by the relative rotative and endwise movement of said tubular member provided with said second mentioned inlet means.

2. A formation testing tool for oil wells and the like, comprising an inner and an outer tubular member fitted to move rotatably and endwise the one within the other, annular packer means carried by said tubular members for engaging the wall of the well bore with sealing effect, and means for limiting the relative rotative and end-- wise movement of said tubular elements, each of said tubular elements having inlet means normally closed by the walls of the other element, the inlet means of the one element being in a transverse plane difierent from the plane of the inlet means of the other element and out of longitudinal alignment therewith, and being relatively positioned so as to be brought into longitudinal alignment upon the relative rotative movement of the one element with respect to the other and the inlet means of both elements registering communicably when said elements are moved longitudinally, in one direction, with respect to each other after such positioning rotative movement.

3. A formation testing tool for oil wells and the like, comprising packer means, an inner and an outer tubular element movably fitted the one within the other and cooperatively carrying said 5 packer means, means for limiting the relative rotative and endwise movement of said tubular elements, said limiting means comprising a longitudinally elongated slot and a transverse slot communicable therewithin one of said tubular elements. and a stud member on the other tubular element located to work in said slots in cooperation with the walls thereof for guiding said tubular elements in their relative movement and effecting the limitation of such movement, each of said tubular elements having separate inlet openings normally closed by the walls of the other element, the inlet openings of the one element being out of longitudinal alignment with theinlet openings of the other element, but being aligned for registration communicably when the tubular elements are relatively moved rotatably and endwise within the specified limits.

4. In a tool of the character described, an inner and an outer tubular element cooperatively carrying an annular packing memb r and movable the one within the other rotatably and longitudinally, each of said tubular elements having separate inlet openings, the inlet openings of the one element being normally out of registerable alignment with the inlet openings of the other element, and means for limiting rotative and endwise movement of said tubular elements with respect to each other, whereby to open and close said inlet openings, said movement limiting means comprising communicating longitudinally and laterally slotted portions of the one tubular element and a stud element on the other tubular element projected and working slidably in said slotted portions of the said one tubular element,

said stud element being relatively strong enough to function in its guiding and limiting capacity under normal conditions but being severable from its tubular element when excess force is applied to said tubular elements to move them relative to each other.

5. In a tool of the character described, a tubular inner element and a tubular outer element cooperatively carrying an annular packing member, said tubular elements being fitted one within the other and movable rotatably and endwise with respect to each other, each of said tubular members having separate inlet openings normally closed by the walls of the other elements said inlet openings being movable into and out of communicable registration by slot-and-stud guiding and limiting means, said guiding and limiting means having provision for separation of said tubular elements under abnormal conditions, at will.

6. In a tool of the character described, an outer tubular element and an inner tubular element cooperatively carrying an annular packing member, said tubular elements being fitted one within the other and movable rotatably and endwise with respect to each other, the outer tubular element having a longitudinally elongated guiding and limiting slot, a laterally offset transverse slot communicating with said longitudinally elongated slot and ailording stop shoulders for limiting endwise movement, and a second laterally oilset transverse slot opposed to said first mentioned transverse slot, communicating at one end with said longitudinally elongated slot, and merging at its opposite end in a second longitudinally elongated slot whose remote end opens at the top of said tubular element, and a stud member on said inner tubular member arranged and projected to work slidably in said slotted portions of said outer tubular member whereby to cooperatively limit the relative movement of said tubular .elements and being movable out of said open-ended slot to effect the removal of said inner tubular mem- -ber from said outer tubular member, at will.

7. A formation testing tool for oil wells and the j like as set forth in claim 1, having controllable inlet means for receiving and entrapping cognate fluid from the formation, said tool having an outwardly opening, normally closed valve capable of retaining the entrapped sample within the tool under normal conditions but openable under pressure of applied fluid supplied to the tool from above the formation.

8. A formation testing tool for oil wells and the like as set forth in claim 1, having means for admitting and entrapping cognate fluid from the formation, and, means for discharging into the formation opening in the region of the tool a fluid under pressure supplied through the tool from above the formation.

9. A formation testing tool as set forth in claim 3, wherein the stud is of such strength as to function under normal conditions in guiding and limiting the relative movement of saidtubular members, but destructible under excessive force thereupon.

10. In a formation testing tool as set forth in claim 1 an outwardly opening valve at the lower end of the tool, said valve normally held releasably closed and retaining the entrapped cognate fluid sample within the tool, but opening under excess premure of fluid supplied through the tool from above the formation.

11. A testing tool as set forth in claim 1, wherein the tubular elements are separable at will under abnormal conditions.

12. A testing toolas set forth in claim 3, wherein an upwardly extending open-ended slot communicates with the transverse slot, whereby' the tubular elements may be separated at will.

HUBERT E. PHILP; 

